Submarine tethered working unit and method of manipulating

ABSTRACT

A submarine tethered working unit is lowered into proximity with an underwater apparatus requiring servicing. The working unit is then maneuvered under its own power into embracing guided relationship with the pylon of the apparatus and the unit then crawls upwardly on the pylon under its own power and locks itself rigidly to the pylon in a position near a removable module of the underwater apparatus. The working unit separates the module from the remainder of the apparatus and carries it to the surface of the water after separation from the pylon.

1 1 Oct. 23, 1973 United States Patent Smith et a1.

SUBM ARINE TETHERED WORKING UNIT AND METHOD OF MANIPULATING 3,550,38812/1970 Smith et 61/69 R Primary ExaminerJ. Karl Bell Md.; Andre GeorgeBrun, Paris, France ABSTRACT [73] Assignee: Westinghouse ElectricCorporation,

Pittsburgh, Pa.

Jan. 7, 1972 [22] Filed A submarine tethered working unit is loweredinto proximity with an underwater apparatus requiring ser- Appl. No.:216,037

vicing. The working unit is then maneuvered under its own power intoembracing guided relationship with the pylon of the apparatus and theunit then crawls [52] US. 61/69 R, 114/16, 166/.5

upwardly on the pylon under its own power and locks itself rigidly tothe pylon in a position near a removable module of the underwaterapparatus. The work- 166/5 ing unit separates the module from theremainder of [56] References Cited the apparatus and carries it to thesurface of the water after separation from the pylon. UNlTED STATESPATENTS I 3,163,221 12/1964 166/.6 15 Claims, 11 Drawing FiguresPATENIEDHU 23 um v sum 1 (IF 4 FIGI f SUBMARINE TETHEREI) WORKING UNITAND METHOD OF MANIPULATING BACKGROUND OF THE INVENTION Underwatermanipulators and working units for use in servicing subsea oil wellequipment and the like are known in the prior art, including entirelyself-propelled submarine working units and units which are tethered fromthe surface of the water. Some examples of the prior art are containedin 11.8. Pat. Nos. 3,166,123; 3,381,485; and 3,550,388.

The need for the present invention arises from the requirement for aworking unit which may be precisely positioned relative to underwaterapparatus and more particularly relative to certain components of theapparatus which are removable. In order to constitute an improvement onthe prior art, the working unit must possess in addition to the aboveability to position itself precisely the additional ability to lockitself securely to the underwater apparatus in a primary workingposition so that the working unit will be able to exert sufficientlypowerful forces on the apparatus to fulfill its mission.

These and other objectives of the invention will become apparent duringthe course of the following detailed description.

SUMMARY OF THE INVENTION The present invention isdirected to asubmersible working unit to be utilized in'connection with underwaterapparatus requiring periodic servicing. The submersible working unitfeatures the ability to maneuver itself into engagement with a pylonbody at the bottom of a body of water and to embrace, of clasp the pylonin such a manner that the working unit may be guided therealong.Following this, the working unit climbs or crawls under its own powertoward the top of the pylon and locks itself firmly to the pylon in aprimary working position, such as adjacent to a removable module of theunderwater apparatus. -While in such position, the working unit mayperform the required servicing of the apparatus and may separate andlift the removable module, transferring the same bodily to the workingunit.-Following this, the-unit disengages the pylon and carries theapparatus module to the surface or to some other required transferpoint.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 10 is a plan view of asubmersible working unit.

in accordance with a modification of the invention; and

FIG. 1 l is a similar plan view showing another modification.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawingfigures in detail and particularly to FIGS. 1 through 3, there is showna submersible working unit having a box-like frame 20 within which maybe mounted removably a diving bell or sphere 22 for service personnel orobservers. The diving bell 22 is centered and cradled in the frame 20 bya circular array of elements 24 consisting of utility gas bottles,buoyancy elements and cushions.

At its lower end and forward corners, the frame. 20 carries rigidforwardly projecting arm structures 26, each of which is bifurcated asshown at 28 for the reception of power-operated engaging and positioningarms 30 which are pivotally attached to the rigid arm structures 26through trunnions 32. The arms 30 are preferably somewhat curvedlongitudinally as best shown in FIG. 3 to enable them to clasp orembrace a cylindrical pylon 34 forming the subsea anchorage and supportof apparatus requiring servicing by the unit 20. Such subsea apparatuswill be referred to in greater detail as the description proceeds. Theengaging and positioning arms 30 are pivoted horizontally about the axesof their trunnions 32 by power operators 36 in the form of a pair ofextensible and retractable cylinder-piston units. The units 36 havetheir cylinder ends pivotally secured at 38 to the interior sides ofrigid arm structures 26' and have their piston rod ends pivotallyconnected as indicated at 40'to the rear ends of the arms 30 inrearwardly spaced relation to the trunnions 32. It may be noted in FIGS.2 and 3 that the engaging and positioning arms 30 are swingable betweenclosed or active positions where these arms embrace the pylon 34 andopen or inactive positions where the arms 30 are divergent. These twopositions are shown in full lines and broken lines in FIG. 3.

Rota'tably mounted on the forward end of each arm 30 is a climbing andguiding wheel 42 forthe working unit having conventional power drivingmeans, not shown. The wheels 42 have, a covering of suitable frictionmaterial on their peripheries to resist. slipping while under power andin contact with the pylon 34. Additional friction rollers 44 which maybe powered-or unpowered are journaled on the top and bottom por-' tionsof the rigid arm structures 26 so as to engage the rearward side of thepylon 34 in upper andlower pairs. The driving means, not shown,for thewheels 42 and rollers 4:4 may be of a conventional nature and may belocated in the center area 46 at the forward side of the frame 26between the upper and lower sets of rollers 44, FIG.; 2. when the arms30are in the active pylonembracing positions, FIG. 3, the wheels 42 aredisposed well forwardly'of the center verticalaxis of the-pylon and therollers 44. are well rearwardly of this-axis.

Therefore, the working unit through its arm structure is embracing thevertical pylon at four approximately equidistantly spaced points aroundthe circumference of the pylon. This very secure engagement of the working unit to the pylon enables the working unit to climb or crawlupwardly on the pylon with precision and stability. When the arms 30 areexpanded to their open divergent positions shown in broken lines in FIG.3, these arms are then generally aligned with the axes of the diverge'ntrollers 44, and together therewith are cabable of guiding or funnelingthe working unit' smoothly into contact with the vertical pylon, as whenthe unit initially engages the pylon after being lowered into the water.The rollers 44 are also adapted toform somewhat resilient bumpers forcushioning the engagement of the working unit with the rigid pylon.

Referring particularly to FIGS. 2 and 3, means is provided on the mobileworking unit to lock the same rigidly to the pylon 34 in a primaryworking position adjacent to a removable module 48 of the subseaapparatus requiring servicing. As shown, the removable module 48 isnormally atop the pylon 34 which is fixed to the sea bottom by knowntechniques. The locking means for the working unit comprises avertically spaced pair of power-operated locking shoes 50 on the centralportion of the frame 20 between the pairs of rollers 44. These shoes arethrust forwardly into firm contact with the rear side of the pylon 34 byconventional power actuator means, not shown, also contained on theframe 20. The shoes 50 are retracted from the pylon during the climbingmovement of the working unit thereon and at all other times except whenthe unit is to be locked fixedly in the primary working position, for example, as shown in FIGS. 1 and 6. Similar poweroperated extendable andretractable locking shoes 52 are located on the interior sides of thearms 30 near the centers of these arms. The shoes 52 are powered byconventional means, not shown. Preferably, the shoes 50 and 52 areoperated substantially in synchronism. The arrangement is such, FIG. 3,that when the working unit is locked in position on the pylon 34 thesets of shoes 50 and 52 are engaging the pylon at three widely spacedcircumferential locations. With the shoes 50 lying on the center line ofthe pylon, the other shoes 52 are positioned somewhat beyond a planethrough the axis of the pylon so that it will not be possible for theworking unit to be dislodged laterally of the pylon axis when in thelocked position.

For maneuvering and propelling the submersible working unit in thewater, as when approaching one side of the pylon 34, FIG. 4, whiletethered from above, a pair of opposite side conventional propulsionunits 52 are provided on the frame 20 near the tops of the armstructures 26 and near the center of the frame 20 as viewed from above,FIG. 3. Additionally, the frame 20 which constitutes the body of theworking unit possesses other features such as side racks 54 for variousportable tools and guide rollers 56 to facilitate mating with certaintypes of deep diving craft. Still additional utility features, not shownin the drawings, may be included in the working unit.

At its top, the box-like frame 20 carries a pair of upstandingtriangular rigid side extensions 58 to the tops of which is. pivoted avertically swingable module manipulating frame 60. The opposite sidemembers of the frame 60 are pivoted near their lower ends to theextensions 58 as shown at 62. Below this point, depending crank arms 64on the frame 60 are pivotally connected as at 66 with power operators 68in the form of extensible and retractable cylinder-piston units. Theseunits are additionally attached pivotally at 70 to the frame 20 near theupper forward comers thereof. The power operators 68 may thus swing theframe 60 from a vertical position shown in full lines in FIG. 1 to anear horizontal working position shown in broken lines.

The manipulating frame 60 is provided at its top with a pivotedcrosshead 72, turned on its pivot by another cylinder-piston unit 74carried by the frame 60. A coupling head 76 for engaging and lifting themodule 48 is provided on the frame 60 coupled with the crosshead 72 byflexible fluid supply hoses 78 through which certain servicing fluidscan be delivered to the subsea apparatus from above through a hose 8Gand a swivel coupling 82 on the crosshead 72. The coupling 76 along withthe crosshead 72 is pivoted to the top of the frame 60 through a crossshaft 84. Also on the crosshead 72 an annular-type ram or jack 86 forraising and lowering the coupling 76 is provided and various portabletools can be passed through the center bore of this annular device so asto enter the interior of the subsea apparatus when the coupling 76 is incommunication therewith as indicated in broken lines in FIG. 1.

In addition to pumping certain servicing liquids into the subseaapparatus and performing other known types of service operations, thepivoting frame 60 with the coupling 76 is utilized to bodily lift themodule 48 from the top of the pylon 34 and to place the module at reston a suitable seat 88 forming a part of the frame 20, after which themodule may be transported to the surface of the water with the entireworking unit. It should be clear that the frame 60 and associatedcomponents is operated in a similar but reverse manner to replace themodule 48 on the top of the subsea apparatus or to install a new module.

The working unit can be tethered to a surface support vessel by the hose80, which may be of the high tensile strength type. If preferred, thetethering may be done through a cable or a cable in addition to thehose. Electrical power may be supplied to the working unit through asuitable electrical cable, not shown. In cases where the working unit isnot buoyant, the tethering hose or cable will support the weight of theunit, and in such a case a constant tension hoisting system ispreferably employed on the surface. .1

OPERATION The method of utilizing and manipulating the abovedescribedworking unit in connection with the required servicing of the underwaterapparatus is as follows, referring particularly to FIGS. 4 through 9 ofthe drawings. In FIG. 4, the tethered working unit has been lowered tothe approximate level of the middle of the pylon 34 and is spacedlaterally from the pylon. Since the pylon is cylindrical and the workingunit is self-guiding into engagement with the pylon, it may approachfrom any direction. The working unit will be subject to up and downmovements of the surface vessel as caused'by sea conditions. Nosignificant horizontal movements from above will be transmitted to theworking unit.

Referring to FIG. 5, the working unit by usingits propulsion devices52', whether propellers, jets or the like, now maneuvers itselfhorizontally toward the pylon 34 and can approach the same from anydirection, asstated. The widely divergent arms 30 and rollers44 will Iserve to gently guide the working unit into proper engagement with thefixed pylon .during theapproach, and the rollers 44 serve as buffers tocushion the contact.

When the working unit is at a maximum vertical position under influenceof surface waves (zero vertical velocity), the arms 30 are closed aroundthe pylon to their positions shown in full lines in FIG. 3'and alsoshown in FIG. 5. The driving means for the climbing rollers 42 or 44, orboth, is set into operation and the climbing mechanism creates apositive link between the unit and pylon and the unit now begins topropel itself upwardly along the pylon toward the primary workingposition shown in FIG. 6. During this period, the constant tensionhoisting system on the surface ship will further absorb oscillationscaused by wave action. The

tether 80 is now slacked off, FIG. 6, and the working unit is completelyindependent of the surface and continues its vertical climb on the pylonuntil it stops with precision at the predetermined working level. Atthis point, the locking shoes 50 and 52 are activated and shift intolocking engagement with the pylon and the working unit now is rigidlyheld on the pylon and stabilized for the performance of its various workfunctions under the most favorable conditions.

Proceeding to FIG. 7, the manipulating frame 60 is now activated tobring the coupling 76 into coupled engagement with the module 48 for thedelivery of servicing fluids to the subsea apparatus through the hoses80 and 78, and so that other known types of servicing may be carriedout. At the proper time, FIG. 8, the removable module 48 is bodilylifted from the top of the pylon 34 by raising the manipulating frame 60back to the vertical. When this has been completed, the ram 86 isutilized to lower the module 48 onto its seat 88, FIG.

2, and the module is now safely stabilized at the top and,

at the bottom by the coupling 76 and the seat 88.

At this time, referring to FIG. 9, the locking shoes 50 and 52 areretracted and the arms 30 are separated to release the pylon 34 and theworking unit may back away somewhat from the pylon using its propulsionmeans 52' and may then be elevated to the surface with the module 48thereon by utilizing the tether 80 and associated hoisting means.

' The invention permits particularly effective use of a tethered workingunit, which unit has the advantage of being clear of the sea bottom atall times so that the propellers and other moving parts will not stir upsediment, thereby allowing the working unit to operate in clear waterwith good visibility for personnel in the bell or sphere 22. In somecases, however, the attaching,

vergent bumpers 110 which serve to guide the unit 104 smoothly intoengagement with the pylon 34. The unit 104 has pivotally mounted on thearm structures 108 a pair of diametrically opposed vertically extendingcrawler mechanisms 112 to securely lock the working climbing and lockingfeatures of the invention may be applied to non-tethered submarine-typeunits. The greatest virtue of the invention lies in the ability of theworking unit to reliably and securely locate and attach itself on'thepylon 34 and to climb up the pylon with precision and to stop thereon ata precise level, followed by secure locking which enables the unit toperform all interventions with reliability and efficiency.

Referring now to FIG. 10, a slightly modified form of working unit 90 isshown having a body portion or frame 92 adapted to receive and supportthe module 48 and a diving bell, such as the bell 22 in FIG. 2. The unit90 has rigid diverging arm structures 94 on the forward 7 side thereofand pivoted power-operated engaging and positioning arms 96corresponding to the arms 30 and being actuated by power means 98. Thearms 96 at their leading ends carry pylon-engaging rollers 100 which maybe unpowered guide rollers. In lieu of the diverging crawler rollers 44of the prior embodiment, the working unit 90 is equipped with avertically extending power-operated caterpillar-type crawler mechanism102 which engages the adjacent side of the pylon 34, with the rollers100 situated forwardly of the axial center of the pylon. A suitablepositive locking means 102' similar to the shoes and 52 is also includedin the unit 90. The general method above-described and illustrated inFIGS. 4 through 9 remains essentially unchanged in connection with theworking unit 90.

FIG. 11 depicts a further modification in which a 6 working unit 104having a body or frame 106 possesses diverging rigid arm structures 108at its forward side. Associated with the arm structures 108 are forwarddiunit in the desired precise position on the pylon 34. Again, themethod as described in connection with FIGS. 4 through 9 is essentiallyunchanged and a further description thereof is thought to be unnecessaryfor a full understanding of the invention.

While the present embodiments have been disclosed with certain degree ofparticularity, it should be observed that the present disclosure hasbeen made by way of example only. It is not desired therefore that theinvention be limited specifically to the disclosed embodiments but it isto be understood that all equivalents, alterations and modificationswithin the spirit and scope of the present invention are herein meant tobe included.

We claim:

I. A method of servicing an underwater apparatus having a body portionsecured to the bottom of a body of water, comprising the steps of:

maneuvering a submersible working unit in the water and thereby causingthe working unit to engage said body portion of the apparatus;mechanically coupling the working unit movably to said body portion atan elevation below the top of thebody portion; and moving the workingunit upwardly on the body portion under its own power by frictionallydriving the working unit along the surface of the body portion, and thenstopping and fixedly locking the working unit near the top of the bodyportion for the performance of servicing operations on the apparatus.

2. The method as defined by claim 1, and said mechanical coupling of theworking unit to said body portion comprising coupling by embracing thebody portion with movable arm means.

3. The method as defined in claim 2, and said moving of the working unitupwardly on the body portion consisting of frictionally driving theembracing arm means upwardly along the surface of the body portion.

- 4. The method as defined by claim 1, and the, additional step ofseparating a removable module from the top of the body portion by meansof the working unit while the working unit is fixedly locked to the bodyportion; and t 1 transferring said module onto the working unit fortransporting to a delivery location.

5. Apparatus for 'servicing'an underwater apparatus having a bodyportion secured to the bottom of a body of water comprising:

a submersible unit maneuverable in the water relative to the bodyportion of said apparatus; propulsion means on said unit to move theunit'toward one side of said body portion;

engaging arms extending from said unit and closing about said bodyportion in an embracing mode when said unit moves into engagement withthe body portion;

power drive means on the unit frictionally engaging the exterior surfaceof the body portion and positively propelling the unit upwardly over theexterior surface to an apparatus servicing position on the body portion;

and additional power means on said unit engaging the body portion tolock the unit fixedly thereto in said apparatus servicing position.

6. The invention as defined by claim 5, and a mechanical manipulatormeans on said unit capable of performing servicing operations while theunit is in said servicing position.

7. The invention as defined by claim 5, and said engaging arms includingat least a pair of divergent arms pivotally secured to one side of saidunit; and

power operating means for said arms causing them to close about saidbody portion after the divergent arms have guided the unit into properlycentered engagement with the body portion.

8. The invention as defined by claim 7, and roller means on saidengaging arms having direct contact with the exterior surface of saidbody portion.

9. The invention as defined by claim 5, and said power drive means onthe unit comprising power driven roller means having frictional contactwith the exterior surface of the body portion when said arms are closedabout the body portion in said embracing mode.

10. The invention as defined by claim 9, and said power drive meansincluding at least one crawler type traction device on said unitfrictionally engaging the exterior surface of said body portion whensaid engaging arms are closed about the body portion.

11. The invention as defined by claim 5, and wherein said additionalpower means to lock the unit fixedly to the body portion comprisesplural power-operated locking shoes movable substantially radially ofthe body portion into rigid clamping engagement therewith at widelyspaced points around the circumference of the body portion, the bodyportion comprising a substantially cylindrical pylon.

12. The invention as defined by claim 5, and said submersible unithaving a frame body portion; and

a diving bell mounted removably within the frame body portion.

13. The invention as defined by claim 6, and said mechanical manipulatormeans comprising a pivoted frame on the top of said unit; and

the latter to be moved relative to said frame.

i i II! II

1. A method of servicing an underwater apparatus having a body portionsecured to the bottom of a body of water, comprising the steps of:maneuvering a submersible working unit in the water and thereby causingthe working unit to engage said body portion of the apparatus;mechanically coupling the working unit movably to said body portion atan elevation below the top of the body portion; and moving the workingunit upwardly on the body portion under its own power by frictionallydriving the working unit along the surface of the body portion, and thenstopping and fixedly locking the working unit near the top of the bodyportion for the performance of servicing operations on the apparatus. 2.The method as defined by claim 1, and said mechanical coupling of theworking unit to said body portion comprising coupling by embracing thebody portion with movable arm means.
 3. The method as defined in claim2, and said moving of the working unit upwardly on the body portionconsisting of frictionally driving the embracing arm means upwardlyalong the surface of the body portion.
 4. The method as defined by claim1, and the additional step of separating a removable module from the topof the body portion by means of the working unit while the working unitis fixedly locked to the body portion; and transferring said module ontothe working unit for transporting to a delivery location.
 5. Apparatusfor servicing an underwater apparatus having a body portion secured tothe bottom of a body of water comprising: a submersible unitmaneuverable in the water relative to the body portion of saidapparatus; propulsion means on said unit to move the unit toward oneside of said body portion; engaging arms extending from said unit andclosing about said body portion in an embracing mode when said unitmoves into engagement with the body portion; power drive means on theunit frictionally engaging the exterior surface of the body portion andpositively propelling the unit upwardly over the exterior surface to anapparatus servicing position on the body portion; and additional powermeans on said unit engaging the body portion to lock the unit fixedlythereto in said apparatus servicing position.
 6. The invention asdefined by claim 5, and a mechanical manipulator means on said unitcapable of performing servicing operations while the unit is in saidservicing position.
 7. The invention as defined by claim 5, and saidengaging arms including at least a pair of divergent arms pivotallysecured to one side of said unit; and power operating means for saidarms causing them to close about said body portion after the divergentarms have guided the unit into properly centered engagement with thebody portion.
 8. The invention as defined by claim 7, and roller meanson said engaging arms having direct contact with the exterior surface ofsaid body portion.
 9. The invention as defined by claim 5, and saidpower drive means on the unit comprising power driven roller meanshaving frictional contact with the exterior surface of the body portionwhen said arms are closed about the body portion in said embracing mode.10. The invention as defined by claim 9, and said power drive meansincluding at least one crawler type traction device on said unitfrictionally engaging the exterior surface of said body portion whensaid engaging arms are closed about the body portion.
 11. The inventionas defined by claim 5, and wherein said additional power means to lockthe unit fixedly to the body portion comprises plural power-operatedlocking shoes movable substantially radially of the body portion intorigid clamping engagement therewith at widely spaced points around thecircumference of the body portion, the body portion comprising asubstantially cylindrical pylon.
 12. The invention as defined by claim5, and said submersible unit having a frame body portion; and a divingbell mounted removably within the frame body portion.
 13. The inventionas defined by claim 6, and said mechanical manipulator means comprisinga pivoted frame on the top of said unit; and a power operator connectedwith said frame to swing it between generally horizontal and generallyvertical positions.
 14. The invention as defined by claim 13, and acoupling head pivotally mounted upon said frame and adapted forattachment to a removable module on the underwater apparatus, wherebysaid module may be Lifted and transferred onto said unit.
 15. Theinvention as defined by claim 14, and a power actuator for said pivotedcoupling head allowing the latter to be moved relative to said frame.